Hydrocarbonaceous liquids (full range or cuts thereof) obtained from oil shale, tar sands, and normally solid coal, i.e., syncrude, generally contain relatively high quantities of nitrogen in various forms, generally five and six member cyclic compounds such as pyridines and indoles. It is desirable in a number of cases to reduce the nitrogen quantity of such syncrude materials, particularly if they are to be used as fuel. However, where there is a high nitrogen content, severe hydrogenation conditions, e.g., high pressure, low space velocity, and the like, are necessary. Such conditions elevate the cost of processing because larger and more expensive hydrogenation reactors are required together with greater hydrogen consumption in the operation.
Thus, it is highly desirable to reduce the nitrogen content of the syncrude feed prior to hydrogenation thereof.
Heretofore the prior art, U.S. Pat. No. 2,704,758 to Wetzel, has employed with nitrogen containing hydrocarbonaceous feeds an extraction step using formic acid, a highly volatile organic acid, followed by a decomposition distillation step for separating the highly volatile organic acid and associated oil from a high nitrogen phase (nitrogen base concentrate). The high nitrogen phase was then subjected to pyrolytic hydrogenolysis which is clearly taught to be non-catalytic and therefore is nothing more than pyrolytic decomposition in the presence of hydrogen. The prior art's extraction with a highly volatile organic acid, distillation for separation, and pyrolytic hydrogenolysis are severe requirements from a commercial point of view.
This invention eliminates such requirements without sacrificing nitrogen removal and with minimum hydrogen comsumption.